As shown in FIG. 1, a prior art pet collar has a strip 1 of cloth or leather. The strip 1 is provided in the outer longitudinal side with a light-reflecting piece 2. In light of the light-reflecting piece 2 being small, the warning effect of the prior art pet collar is relatively poor.
As shown in FIG. 2, another prior art pet collar comprises a flexible tube 3 in which a plurality of light-emitting bodies 4 are disposed in conjunction with a wiring 5. The flexible tube 3 is pervious to light and is provided at one end with a head 6 in which a control board is housed. A retaining hook 7 is attached to the head 6. This prior art pet collar is not cost-effective. In addition, the flexible tube 3 and the head 6 of the pet collar cause discomfort to a pet when the collar is worn around the neck of the pet.